Imaging method for improving signal-to-noise ratio of high-speed SAR platform based on continuous pulse coding

Abstract

The invention discloses an imaging method for improving the signal-to-noise ratio of a high-speed SAR platform based on continuous pulse coding. The imaging method mainly solves the problem that imaging cannot be conducted on the high-speed SAR platform in the prior art. The implementation scheme comprises the steps of designing a pulse string signal, and repeatedly transmitting the pulse string signal; obtaining an original aliasing echo signal according to the transmitted pulse string signal; constructing a multivariate linear equation set according to the form of the transmitted pulse string signal, specifically, selecting a plurality of sub-equation sets with the same number of equations from the multivariate linear equation set according to the determined step length, and solving a complete echo signal to obtain de-aliasing echo signals; and uniformly grouping the de-aliasing echo signals and superposing the de-aliasing echo signals in the same group, and performing SAR imaging onthe superposed echo signals according to equivalent pulse repetition frequency. The method can improve the azimuth sampling rate, eliminates the azimuth spectrum aliasing of echoes, achieves the imaging on a high-speed platform, and can be used for topographic surveying and mapping, marine observation, disaster forecasting, crop evaluation and celestial body observation.

Description

technical field [0001] The invention belongs to the technical field of digital signal processing, and in particular relates to an imaging method for improving the image signal-to-noise ratio of a high-speed SAR platform, which can be used for terrain surveying and mapping, ocean observation, disaster forecast, crop evaluation and celestial body observation. Background technique [0002] Synthetic Aperture Radar (SAR) is an all-weather and all-weather long-range detection method, which has the ability to image targets. Radar image signal-to-noise ratio (SNR) is one of the important indicators used to measure the imaging quality of a radar image, which directly determines whether accurate target information can be obtained from the radar image. For military use, there are battlefield reconnaissance, target recognition, ground attack, etc., while for civilian use, there are terrain surveying and mapping, ocean observation, disaster forecasting, crop evaluation, and astronomical...

AI Technical Summary

Problems solved by technology

[0004] To recover multiple sets of complete echoes, it is necessary to transmit an overly long pulse signal. Since the longer the transmitted signal, the greater the pulse train repetition period, that is, the higher the pulse train repetition frequency. Therefore, according to the sampling theorem, if this method is applied to a high-speed SAR platform, the azimuth spectrum of the echo will alias due to the pulse train repetition frequency not being high enough, and the imaging effect will be poor

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